Bimetal synergistic catalysis is a powerful strategy for developing efficient and novel organic reactions, which can achieve some challenging chemical reactions, especially those that are difficult to achieve with a single metal catalyst. In addition, elucidating the evolution process and catalytic effect of two different transition metal catalysts in the reaction system is one of the important and challenging goals in the research of bimetallic synergistic catalysis.
Wang Xiaoming, the research group of State Key Laboratory of Metal Organic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, is committed to studying the reaction system involving polymetallic species, including the development of enzyme like dual polynuclear metal catalysts and on-site clustering and catalysis of metal species. The team has made some progress in dual (multi) nuclear metal catalysis work. Recently, based on this, they reported the carbene divergent bifunctional group reaction catalyzed by metal copper/rhodium bimetallic synergy. The reaction can convert diazonium, terminal alkynes, and allyl substrates into 1,5-alkyne compounds in one step, which can be used for various subsequent transformations to quickly construct cyclic molecular frameworks. In addition, when using propargyl alcohol as the terminal alkyne substrate, the reaction will undergo Meyer Schuster rearrangement to generate acyl allylation products of carbenes. Researchers further focused on the evolution process of two metal catalyst precursors. The reaction between acetylene copper and diphosphine ligands resulted in the formation of tetranuclear copper clusters, indicating that copper species may undergo clustering. During the obvious induction period of the reaction, mercury poisoning experiments, commercial copper nanoparticle substitution experiments, and transmission electron microscopy all indicate that the pre catalyst cuprous chloride may undergo on-site clustering in the reaction system, generating copper nanoparticles and catalyzing the reaction between carbene and terminal alkyne. The dual core rhodium catalyst may dissociate in the reaction system, generating a single core rhodium species coordinated with a dual phosphine ligand. Research suggests that both binuclear rhodium and dissociated mononuclear rhodium may catalyze the process of allyl alkylation. The synergistic effect of the carbene insertion reaction catalyzed by copper nanoparticles in the on-site cluster and the allyl substitution reaction catalyzed by metal rhodium complexes is considered to be the catalytic process experienced by this reaction.
The relevant results are published in the Journal of the American Chemical Society. The research work has received support from the Ministry of Science and Technology, the National Natural Science Foundation of China, and the Shanghai Municipal Science and Technology Commission.
Paper link
Copper/rhodium bimetallic synergistic catalytic carbene divergent bifunctional group reaction
